Flexible stay-bolt.



No. 672,852. Patented Apr. 23, I90l.

J. B. BARNES.

FLEXIBLE STAY BOLT.

A lication filed Feb. 21, 1901.)

UNITED STATES PATENT OFFICE.-

JOSHUA BARTLETT BARNES, OF SPRINGFIELD, ILLINOIS.

' FLEXIBLE STAY- BOLT.

SPECIFICATION forming part of Letters Patent No. 672,852, dated April 23, 19 01. Application filed February 21, 1901. Serial No. 418,311. (No model.)

To all whom it may concern:

Be it known that I, JOSHUA BART ETT BARNES, a citizen of the United States, residing at Springfield, Sangamon county, Illinois, have invented certain new and useful Improvements in Flexible Stay-Bolts, of which the following is a specification.

My invention relates to that class of staybolts which are used for the purpose of stayin g sheets of locomotive and other steam boilers against the steam -pressure within the boiler.

The principal object of the invention is to provide a simple, economical, and efficient flexible stay-bolt mechanism by which the head may be held substantially flush with the boiler-sheet and be easily inserted into or withdrawn from operative position, and when in operative position a perfectly steam-tight joint is effected, while at the same not only is the connection flexible to permit the relative longitudinal movement of the inner and outersheets under expansion and contraction, but a vertical lifting movement is permitted to the head of the bolt,.which is desirable also.

The invention includes the features, combinations, and details of construction hereinafter described and claimed.

The invention is illustrated in the accompanying drawings, in which- Figure 1 is a side elevation, partly in section, of a stay-bolt in connection with the inner and outer sheets of a boiler. Fig. 2 is an end view of the bolt-head. Fig. 3 is an elevation, partly in section, of the threaded cup. Fig. 4 is an end view of the same; and Figs. 5 and 6 are side and end views, respectively, of the sealing-plug.

In the art to which this invention relates it is well known that the use of flexible stay bolts is advantageous in that they enhance the efficiency, and consequently the safety, of the boiler under high pressure and prolong the life of the same. It is also well known that at the point of connection with the boiler it is highly desirable to have mechanism which will be practically flush with the surface of the boiler-sheet.- It is further desirable that the head of the bolt should be able to have some vertical play in relation to the outer sheet, as in starting a fire in the furnace the inner shell expands first; but at the same time the head of the bolt must be connected in such a manner as to make an absolutely steam-tight joint irrespective of the relative workings of the parts under expansion and contraction.

In constructing a stay-bolt in accordance with rnyimprovements I provide a bolt u, having a substantially hemispherical head I) at one end and a threaded portion 0 at the other end.

To stay a boiler-that is, to oppose the internal steam-press ure-Iinsert a hollow or tubular plug din the outside shell 6 of the boiler. While I speak of this plug as a tubular plug, it will be seen that it is not truly cylindrical on its exterior, but is tapering or in the shape of a truncated cone, so that as it is screwed in it tends to wedge and produce an extremely tight joint. This plug is provided with an internal cu p-shaped bore, which is preferably the counterpart of the bolt-head, and the inner opening is of smaller diameter than the external opening of the bore. The outer surface of the hollow plug, which, as before stated, is tapering, is threaded to engage with the corresponding screw-threaded opening in the boiler-sheet. These screw-threads only extend for a portion of the length of the plug, and thus leave a practically smooth portion at one end of a diameter less than the bottom of the threads.

When the hollow plug or cupisin position in the outer sheet, the bolt is passed through it and its threaded end engaged with the inside sheet g. The head of the bolt is flat and is provided with an angular recess h, preferably -square, into which a key-wrench may be inserted, so that the bolt may be turned into place or until its head is seated accurately in the cupped bore of the plug and all looseness taken up.

As under the expansion hereinbefore referred to the head will occasionally lift from its seat it is necessary that means be provided for sealing the cuppedloore of the plug against the escape of steam without interfering with the said lifting movement of the head of the plug. In order to attain this result, the outer portion of the cupped bore-which is also taperedis screwthreaded, and into this threaded portion I insert a tapered screw-plug 11, which has a fiat inner face. The outer face of the sealing-plug is provided with a recess j to receive a key-Wrench, by which it may be inserted into and out of position.

By reason of the plug being tapered it will be seen that not only in the screwing in of the plug is a tight closure of the cupped bore elfected, but the tendency of the sealing-plug to expand the cupped plug tends to expand it against the Walls of the opening in the outer sheet in which said cupped plug is seated, and thus a still tighter joint is secured.

The principal advantages incident to the use of my flexible stay-bolt are, first, it provides a mechanism which is substantially flush with the outside surface of the boilershell, and thus permits of padding or similar material being bolted to the shell; secondly, the bolt can be readily removed or inserted at any time without destroying or removing the hollow plug or cup, and by this means the longer bolts, which are removed from some parts of the boiler by reason of wear or damage to their inner ends and which are readily removed by cutting off the headed ends and unscrewing them, may be used again by cutting off the said threaded ends and rethreading them and using them at points requiring shorter bolts; thirdly, the flat head of the bolt and sealing-plug with the space between allows vertical play of the bolt-head with relation to its seat, and, finally, the tapered cupped plug, in combination with the tapered sealingplug, efiectually seals the joint against the escape of steam under pressure.

Having thus described my invention, What I claim is 1. In combination with the innerand outer sheets of a boiler, a hollow cupped plug having a tapered exterior threaded and screwed into the outer boiler-sheet substantially flush with the surface thereof, a bolt having its inner end engaging the inner boiler-sheet and its outer end provided with a head seated in said cupped plug, and a tapered sealingrplug threaded to engage corresponding threads in the interior of said cupped plug, substantially as described.

2. In combination with an outer boilersheet having a screw-threaded hole, of a hollow plug having a cupped and threaded bore, and having at its outer end an enlarged portion with an external screw-thread screwed into the outer-boiler-sheet hole flush with the outside thereof, a stay-bolt screwed into said inner-boiler-sheet hole and provided with a head engaged with the bore in said plug, and a sealing-plug screwed into the threaded bore of said plug, substantially as described.

3. In combination with an outer boilersheet having a screw-threaded hole, a plug having at its outerend an enlarged externallyscrew-threaded portion screwed into said hole, flush with the outer face of the boiler-sheet,

an inner boiler-sheet, a bolt engaged with said inner boiler-sheet and having a head engaging in a cupped bore in said plug, and a sealing-plug in the outer end of the bore in said plug, substantially as described.

4:. In combination with a boiler-sheet, a hollow cupped plug having at its outer end an externally screw-threaded portion screwthreaded therein, a second boiler-sheet, a staybolt having threaded engagement at one end with the second boiler-sheet and provided with a head at the other end engaging the hollow cupped plug and having a key-wrench recess in the head thereof, and a sealing-plug screwthreaded into the bore of the hollow plug to hermetically seal the same and provided with a key-wrench recess therein.

In testimony whereof I afiix my signature in presence of two witnesses.

JOSHUA BARTLETT BARNES.

Witnesses:

A. B. MARS, E. R. J EFFERY. 

